Mepivacaine: Action as a Local Anesthetic

Mepivacaine (trade name Scandicain and generics) is a medium-short acting local anesthetic from the group of aminoamides. It was introduced in the early 1960s and has become especially established in dentistry and regional anesthesia. In Germany, mepivacaine is available as 2 percent and 3 percent injection solution, often combined with or without a vasoconstrictor such as epinephrine or norepinephrine. The average duration of action of about 1 to 3 hours makes mepivacaine the preferred choice for short to medium-length procedures, particularly in dental practice.

Mepivacaine has some pharmacological advantages over lidocaine and bupivacaine in specific indications. It has less intrinsic vasodilatory activity than lidocaine, which allows for a longer duration of action without epinephrine addition. This property is important in patients with contraindications to vasoconstrictors such as severe hypertension, hyperthyroidism, or in procedures in end-artery areas such as fingers or penis. Compared to bupivacaine, mepivacaine has faster onset of action and shorter duration of action with significantly lower cardiotoxicity.

Mechanism of Action

Mepivacaine reversibly blocks voltage dependent sodium channels in the nerve membrane. By binding, it prevents sodium influx, which is required for the initiation and conduction of action potentials. Without action potentials, sensory stimuli such as pain, temperature, and touch cannot be transmitted to the central nervous system, and motor commands cannot reach the muscles. The effect is completely reversible and ends once the local anesthetic is removed from the tissue.

Pharmacokinetically, mepivacaine has an onset of action of 3 to 5 minutes and a duration of action of 1 to 3 hours, depending on concentration, location, and vasoconstrictor addition. Plasma protein binding is approximately 75 percent. Metabolism is hepatic via N demethylation and hydroxylation. The elimination half-life is approximately 1.9 hours for adults and approximately 9 hours for newborns due to immature hepatic metabolism.

Compared to lidocaine, mepivacaine has less inherent vasodilation, which extends the duration of action without epinephrine addition. This is clinically relevant because mepivacaine in 3 percent concentration without vasoconstrictor achieves sufficient duration of action for many dental procedures, while pure lidocaine without vasoconstrictor wears off more quickly.

Areas of Application

• Dentistry: infiltration anesthesia and regional anesthesia for routine dental procedures such as fillings, root canal treatments, extractions, periodontal treatments
• Regional anesthesia: peripheral nerve blocks such as brachial plexus, femoral, sciatic, often in combination with longer-acting substances
• Spinal and epidural anesthesia: in specific indications for shorter procedures, now largely replaced by lidocaine or bupivacaine
• Wound infiltration and skin anesthesia for minor surgical procedures
• Patients with contraindication to vasoconstrictors: mepivacaine without epinephrine as an alternative

Mepivacaine is used particularly frequently in dental practice because in 3 percent without epinephrine it provides adequate anesthesia for standard procedures, which is beneficial in patients with cardiac pre-existing conditions or contraindications to epinephrine.

Dosage and Administration

Dentistry infiltration anesthesia: 1 to 1.8 ml mepivacaine 3 percent without epinephrine or 2 percent with epinephrine per procedure.

Dentistry regional anesthesia: 1.8 to 3.6 ml.

Peripheral nerve blocks: 5 to 40 ml mepivacaine 1 to 1.5 percent depending on block. Maximum dose 400 mg per single block.

Wound infiltration: mepivacaine 0.5 to 1 percent, volume according to wound size.

Maximum single dose adults: 4.4 mg per kg, usually not more than 300 mg without vasoconstrictor, 400 mg with vasoconstrictor.

Pediatric: 4 mg per kg as a rule, individual adjustment in pediatric anesthesia.

Administration: injected slowly, aspiration test before each injection to avoid intravascular injection. Observation for early signs of systemic toxicity (dizziness, tinnitus, perioral numbness).

Renal insufficiency: no adjustment for single dose, caution with continuous use. Liver insufficiency: reduced dose with severe liver dysfunction due to slowed metabolism.

Side Effects

Frequent: hypotension, bradycardia, nausea, vomiting, dizziness, pain at injection site, local swelling.

Occasional: headache, paresthesias, allergic skin reactions (rare with aminoamides), transient visual disturbances.

Rare and very rare: systemic toxicity with intravascular injection or overdose. Symptoms: central excitation with tinnitus, dizziness, perioral numbness, convulsions, then central depression with unconsciousness. Cardiac: hypotension, bradyarrhythmias, asystole. Mepivacaine has lower cardiotoxicity than bupivacaine.

Allergic reactions: very rare with aminoamides, more frequent with preservatives such as methylparaben or sulfites.

Methemoglobinemia: mepivacaine has significantly lower risk compared to prilocaine, theoretically possible with overdose.

When used in end-artery areas (fingers, penis, toes) without vasoconstrictor: avoid circulatory disorders, as epinephrine addition may be contraindicated here.

Drug Interactions

• Other local anesthetics: additive toxicity, observe cumulative maximum dose.
• Class Ib antiarrhythmics (lidocaine, mexiletine): additive effect on sodium channel.
• Beta blockers: with mepivacaine solutions containing epinephrine, increased hypertensive response due to unopposed alpha adrenergic activity.
• MAO inhibitors and tricyclic antidepressants: with epinephrine addition, increased hypertension.
• Sulfonamides: theoretically reduced antibacterial activity, clinically usually not relevant.
• CYP1A2 inhibitors such as fluvoxamine, ciprofloxacin: increased mepivacaine levels, clinically rarely relevant with single administration.

Special Notes

Pregnancy: mepivacaine crosses the placenta. Less frequently used in obstetrics than bupivacaine or ropivacaine due to fetal bradycardia and acidosis risk. Nursing: considered compatible with single use for dental treatment.

Children: established in pediatric anesthesia and dentistry, weight-adapted dosing.

Elderly patients: reduced dose, slower injection, as hypotension and bradycardia occur more frequently.

Contraindications: known hypersensitivity to aminoamide local anesthetics, severe conduction disorders, decompensated heart failure, severe hypotension, obstetric specifics as per indication.

Before use: history of allergies, cardiac pre-existing conditions, concomitant medications, volume status. Emergency equipment with lipid emulsion (Intralipid) in case of systemic toxicity, resuscitation readiness.

In case of systemic toxicity: immediate stop of injection, airway management, anticonvulsant therapy with benzodiazepines, lipid emulsion 1.5 ml per kg as bolus, then 0.25 ml per kg per minute. Extended resuscitation following ALS algorithms.

Lifestyle: after dental treatment with local anesthesia, avoid very hot foods or beverages, as the numb sensation increases burn risk. Also do not bite into the numb lip or cheek.

Ability to drive: usually not impaired after dental local anesthesia. After regional anesthesia, individual assessment, usually 24 hours off recommended.

You May Also Be Interested In

• Lidocaine, short-acting local anesthetic
• Articaine, local anesthetic in dentistry
• Bupivacaine, long-acting local anesthetic
• Ropivacaine, long-acting local anesthetic
• Prilocaine, aminoamide local anesthetic

Frequently Asked Questions

Sources

• Gelbe Liste, Mepivacaine Active Ingredient Profile
• BfArM, Federal Institute for Drugs and Medical Devices
• German Society for Anesthesiology and Intensive Care Medicine
• National Association of German Dentists (BZÄK)
• AWMF Guidelines on Dental Local Anesthesia and Regional Anesthesia